From his recent experience, Eldrian understood that crystalline rocks were his best bet to find something that could hold mana. They did not need to evolve like celestial ores and higher-ranked metals to be capable of this. They just need to have existed in a mana-rich area for long enough.
'Mana rich area-' Eldrian laughed but did not give up. Continuing his search, especially since he had found that the area had amethysts crystals in abundance.
He knew that this was the crystal that given enough time evolved into Mov Crystals, and possibly even Magic Crystals. And while most of the crystals in the stream seemed to not be of great quality, that did not disparage Eldrian.